Glucose is a universal nutrient preferred by most organisms and serves essential roles in energy supply, carbon storage, biosyntheses, and carbon skeleton and cell wall formation. The ability to sense glucose and its deprivation is of fundamental importance in organisms as diverse as E. coli, yeast, flies, mammals, and plants. The significance of glucose as a direct and central signaling molecule in multi-cellular animals and plants has only been recently recognized. In plants whose life revolves around sugar production through photosynthesis, glucose has emerged as a key regulator of many vital processes, including embryogenesis, germination, seedling development, root, stem and shoot growth, carbon and nitrogen metabolism, reproduction, stress responses, and senescence. Our goal is to understand how plants sense glucose signals to control gene expression and modulate growth and development. Studies of glucose responses in plants will enhance our general understanding of glucose signaling mechanisms conserved in other eukaryotes from yeast to mammals. Complementary genomic, proteomic, genetic, molecular, biochemical, and cellular strategies and tools will be used to study glucose signaling pathways in Arabidopsis thaliana as a plant model. Four specific aims are: Aim 1. Genome-wide identification and molecular genetic analysis of glucose responsive genes. We will combine the power of glucose signaling mutants and global gene expression profiling to identify glucose responsive genes and perform functional analysis of selected target genes. Aim 2. Proteomic and genetic analysis of the HXK1 protein complexes in glucose signaling. We will identify the key components of the nuclear HXK1 protein complexes and investigate the function of novel regulatory genes in glucose signaling using genetic, cellular and biochemical tools. Aim 3. Genetic analysis of the gin2 suppressor (g/s) mutants. A genetic approach will be taken to identify novel genes involved in HXK1-mediated signaling. Aim 4. Genomic and reverse genetic analysis of glucose deprivation responses. We will study the functions of Arabidopsis protein kinases (KIN10 and KIN11) that control diverse genes in glucose deprivation and stress responses.